Ivanov, O. V., and I. V. Orlovs’kyi. 2017. “Asymptotic Properties of $M$-Estimates of Parameters in a nonlinear regression Model With Discrete Time and Singular Spectrum”. Ukrains’kyi Matematychnyi Zhurnal 69 (1), 28-51. https://umj.imath.kiev.ua/index.php/umj/article/view/1674.